XAF1 / XIAP-associated factor 1 · Western blot design guide

Design a Western Blot for XAF1

Source-linked XAF1 Western blot protocol options, expected-band and isoform facts, troubleshooting for weak or shifted signal, and recommended anti-XAF1 WB antibodies. Everything you need to plan the experiment before you commit precious samples.

Evidence assembled September 2026 · For research use; verify linked source records and product datasheet before use

Western blot protocol sheet for XAF1: expected band ~34.6 kDa, hero antibody A03432, catalog values and labelled standard workflow; separate PMC comparisons on the guide — Printable **XAF1** Western blot protocol sheet — expected band ~34.6 kDa, antibody A03432, controls and PMC citations. Open the full XAF1 WB guide →

Navigate to: Protocols Band Controls Antibodies

XAF1 Western Blot Experimental Design Guide

Expected bands, source-linked protocol options, controls and antibodies — the at-a-glance facts below, then the full design guide.

Must know before running

	Expected band	~34.6 kDa
	Gel	12–15% (standard starting point)
	Positive control ⓘ	Duodenum (IHC candidate; verify WB) +4 more
	Negative control ⓘ	Adipose tissue (IHC candidate; verify WB)

Important caveats

Reasons your observed band may differ from the expected size.

	PTM	—
	Caveat	—
	Gene-set association	MSigDB Hallmark membership
	Isoform	7 isoform(s)

Section 1

Source-Linked XAF1 Western Blot Protocol Options

The A03432 protocol combines labelled catalog values with standard starting conditions. Published comparisons retain their own sample, reagent and detection scope.

Recommended Western blot protocol parameters
Sample / lysate	human spleen lysate (catalog A03432)
Gel %	12–15% (standard starting point)
Load	20–30 µg total protein per lane; optimize for abundance (standard starting point)
Transfer	Standard semi-dry transfer; verify efficiency (standard starting point)
Membrane	0.45 µm PVDF (standard starting point)
Blocking	5% milk or 5% BSA in TBST (standard starting point)
Primary antibody	A03432 · (A) 0.5 , (B) 1 , and (C) 2 μg/mL (catalog A03432)
Primary incubation	Overnight at 4 °C (standard starting point)
Secondary antibody	Species-matched HRP conjugate at validated dilution (standard starting point)
Secondary incubation	1 h at room temperature (standard starting point)
Wash	3 × 5 min in TBST (standard starting point)
Detection	ECL; bracket exposures to avoid saturation (standard starting point)

Section 2

What Is the Expected XAF1 Western Blot Band Size?

XAF1 is predicted at 34.6 kDa; seven isoforms could affect migration, but no empirical band size or distinct isoform pattern is supplied.

What am I looking at on my blot?
Band near 34.6 kDa	consistent with the predicted XAF1 mass; identity requires controls
Additional bands at other positions	could reflect named XAF1 isoforms, whose migration is unreported
Band in a nuclear fraction	consistent with XAF1's nuclear location
Band in a mitochondrial fraction after TNF treatment	consistent with reported XAF1 translocation

💡Expected XAF1 appearanceXAF1 has a predicted mass of 34.6 kDa, but no empirical band size is supplied; verify a candidate band with an XAF1 depletion control.

How each factor affects band size
Predicted molecular mass	places the reference band near 34.6 kDa
Isoform 1	its individual mass and migration are not supplied
Isoform 2	may migrate differently; its mass is not supplied
Isoform 3	may migrate differently; its mass is not supplied
Isoform 4	may migrate differently; its mass is not supplied
Isoform 5	may migrate differently; its mass is not supplied
Isoform 6	may migrate differently; its mass is not supplied
Isoform 7	may migrate differently; its mass is not supplied

Why is my band missing or off?
Situation	Likely cause	Next action
No band in lysate	XAF1 abundance or antibody detection may be insufficient	check a positive control and compare XAF1 depletion with the untreated sample
Band higher than expected	an alternative isoform is possible, but its migration is unknown	compare with an XAF1 depletion control
Band lower than expected	an alternative isoform is possible, but its migration is unknown	compare with an XAF1 depletion control
Multiple bands	XAF1 has seven named isoforms, but distinct bands are unconfirmed	compare bands before and after XAF1 depletion
Weak or no signal	XAF1 can occupy cytoplasmic, nuclear, or mitochondrial compartments	check the relevant fractions with compartment markers and an XAF1 control

Source: UniProt Q6GPH4 Human Protein Atlas product datasheet (A03432)

Experiment evidence

Western blot images showing XAF1 band

A03432 · XAF1

A03432-1 · XAF1

PA1218 · XAF1

← swipe / scroll for more images →

Real WB data behind the band-size expectations in this section.

Sample controls for XAF1 Western blot

🧪HPA-IHC candidate guidance (verify in WB): For positive controls for XAF1 in Western blot, you can use duodenum tissue lysate, where HPA reports high expression.

Positive control: Duodenum (IHC candidate; verify WB)

Negative control: Adipose tissue (IHC candidate; verify WB)

Loading controls: Run GAPDH, β-actin, and a total-protein stain such as Ponceau alongside the samples.

⚠️Feasibility: XAF1 is intracellular, but verify the expected difference between duodenum and adipose tissue in your lysates.

HPA tissue expression evidence for XAF1

Comprehensive Human Protein Atlas IHC scoring per tissue. Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.

Higher expression tissues · candidate positive controls from IHC

Tissue	Cell type	Level	Evidence	Source
Duodenum	glandular cells	High	Protein (IHC)	HPA →
Endometrium	glandular cells	High	Protein (IHC)	HPA →
Kidney	cells in tubules	High	Protein (IHC)	HPA →
Rectum	glandular cells	High	Protein (IHC)	HPA →
Small intestine	glandular cells	High	Protein (IHC)	HPA →

Lower expression tissues · IHC evidence, not confirmed WB-negative controls

Tissue	Cell type	Level	Evidence	Source
Adipose tissue	adipocytes	Not detected	Protein (IHC)	HPA →
Cerebellum	cells in granular layer	Not detected	Protein (IHC)	HPA →
Cervix	glandular cells	Not detected	Protein (IHC)	HPA →
Lung	alveolar cells	Not detected	Protein (IHC)	HPA →
Lymph node	non-germinal center cells	Not detected	Protein (IHC)	HPA →

Section 3

Advanced XAF1 Western Blot Tips

Deeper troubleshooting and optimisation questions for XAF1, answered from its protein features.

Where should the canonical XAF1 band appear?

Band shift · The 301-residue canonical sequence has a predicted mass of 34.6 kDa. Use that as a reference, but no observed band position is supplied, so an apparent band shift cannot be inferred.

Which XAF1 isoforms could produce smaller bands?

Isoforms · Seven isoforms are listed. Relative to the canonical sequence, isoform 6 lacks residues 1–102; isoforms 3 and 4 lack residues 142–301; and isoform 5 replaces residues 141–301 with a shorter sequence. Isoforms 2 and 4 also lack residues 57–75. These changes make isoforms worth considering when evaluating smaller bands.

Compare the antibody epitope with the annotated sequence changes. An epitope within residues 142–301 is absent from isoforms 3 and 4 and partly replaced in isoform 5. Residues 1–102 are absent from isoform 6. UniProt coordinates here refer to the supplied canonical sequence; antibody or paper numbering may differ.

Do annotated modifications explain an XAF1 band shift?

PTM · The supplied features list no modified residues or glycosylation sites. They therefore provide no specific modification to test as an explanation. Even an annotated modification would not, by itself, establish a visible band shift.

Does this guide establish induction of XAF1?

Induction · No general induction response is established by this guide. A pathway or gene-set association is not evidence of induction in a particular specimen. Verify the relevant treatment and control in a target-specific experiment.

How should transfer be checked for XAF1?

Transfer · Standard workflow guidance: verify transfer efficiency for the intended target size before interpreting a weak signal. Use total-protein assessment and optimize transfer for the membrane, gel and apparatus; the labelled catalog values take precedence.

How should blocking be optimized?

Blocking · Standard workflow guidance: follow the A03432 datasheet where specified. Otherwise compare 5% milk or 5% BSA in TBST; for a phospho-specific assay start with BSA. Optimize background and specific signal with matched controls.

How should XAF1 be quantified across cellular fractions?

Quantitation · XAF1 is reported in the cytoplasm and nucleus and moves to mitochondria upon TNF treatment. Quantify comparable fractions separately and account for fraction recovery when interpreting changes in mitochondrial signal. A stronger mitochondrial band alone does not establish a change in total XAF1.

Does TNF treatment increase XAF1 expression?

Interpretation · The supplied feature says XAF1 translocates to mitochondria upon TNF treatment; it does not establish increased protein abundance. Compare matched whole-cell samples to assess total XAF1, and mitochondrial fractions to assess the reported redistribution.

First compare band patterns with the seven annotated isoforms and the antibody epitope. Sequence deletions and replacements could change which isoforms the antibody detects, but the supplied features give no observed band positions and cannot identify an unexpected band by size alone.

Boster reagents

XAF1 Western Blot Antibodies

Catalog antibodies with Western blot application and product-specific WB images. Evaluate suitability with the reported sample, controls and experimental conditions.

Real WB data Western blot analysis of XAF-1 in human spleen lysate with XAF-1 antibody at (A) 0.5 , (B) 1 , and (C) 2 μg/mL, respectively.

Anti-XAF-1 Antibody

Cat # A03432

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Real WB data

Western blot analysis of XAF1 using anti-XAF1 antibody (A03432-1). Electrophoresis was performed on a 5-20% SDS-PAGE gel at 70V (Stacking gel) / 90V (Resolving gel) for 2-3 hours. The sample well of each lane was loaded with 30 ug of sample under reducing conditions. Lane 1: human placenta tissue lysates, Lane 2: human 293T whole cell lysates, Lane 3: human Jurkat whole cell lysates. After electrophoresis, proteins were transferred to a nitrocellulose membrane at 150 mA for 50-90 minutes. Blocked the membrane with 5% non-fat milk/TBS for 1.5 hour at RT. The membrane was incubated with rabbit anti-XAF1 antigen affinity purified polyclonal antibody (Catalog # A03432-1) at 0.5 μg/mL overnight at 4°C, then washed with TBS-0.1%Tween 3 times with 5 minutes each and probed with a goat anti-rabbit IgG-HRP secondary antibody at a dilution of 1:5000 for 1.5 hour at RT. The signal is developed using an Enhanced Chemiluminescent detection (ECL) kit (Catalog # EK1002) with Tanon 5200 system. A specific band was detected for XAF1 at approximately 35 kDa. The expected band size for XAF1 is at 35 kDa.

Anti-XAF1 Antibody Picoband®

Cat # A03432-1

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Real WB data

Western blot analysis of XAF1 using anti-XAF1 antibody (PA1218). Electrophoresis was performed on a 10% SDS-PAGE gel at 80V (Stacking gel) / 120V (Resolving gel) for 2 hours. The sample well of each lane was loaded with 30 ug of sample under reducing conditions. Lane 1: human Jurkat whole cell lysates. After electrophoresis, proteins were transferred to a nitrocellulose membrane at 150 mA for 50-90 minutes. Blocked the membrane with 5% non-fat milk/TBS for 1.5 hour at RT. The membrane was incubated with rabbit anti-XAF1 antigen affinity purified polyclonal antibody (PA1218) at 0.5 μg/mL overnight at 4°C, then washed with TBS-0.1%Tween 3 times with 5 minutes each and probed with a goat anti-rabbit IgG-HRP secondary antibody (Catalog # BA1054) at a dilution of 1:5000 for 1.5 hour at RT. The signal is developed using an ECL Plus Western Blotting Substrate (Catalog # AR1196-200) with Tanon 5200 system. A specific band was detected for XAF1 at approximately 35 kDa. The expected band size for XAF1 is at 35 kDa.

Anti-XIAP-associated factor 1 XAF1 Antibody Picoband®

Cat # PA1218

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All three listed anti-XAF1 antibodies have Western blot images using human samples: A03432 with spleen, A03432-1 with placenta, 293T, and Jurkat, and PA1218 with Jurkat. Mouse reactivity is listed for A03432, but its supplied blot shows human lysate only.

Which to pick: For mouse samples, A03432 is the only listed mouse-reactive option; its shown blot uses human spleen. For human samples, choose by the closest documented specimen: A03432-1 shows placenta, 293T, and Jurkat, while PA1218 shows Jurkat.

Source: BosterBio XAF1 gene-info card — filtered to Western-blot-capable antibodies; each card shows that product's actual WB validation figure.

References

UniProt Consortium. UniProt entry Q6GPH4.
Human Protein Atlas. XAF1 tissue expression.
PMC4868675 — target-verified WB comparison
PMC4170645 — target-verified WB comparison
PMC5085151 — target-verified WB comparison